Database: Dhimmi (Non-Muslims)
The term dhimma means "obligation" and was used in Abbasid times to refer to conquered peoples under a specific tax obligation to the government. People of the dhimma, called dhimmis, were often descendants of the Christians, Jews, Zoroastrians, and others whose communities came under the control of the Abbasid Empire. They made up a large part of the empire's population.
Their status was justified by Quranic verses distinguishing between monotheistic non-Muslims and polytheistic "pagans". The latter had to be converted, while the former were entitled to their life, their property, and their freedom of religion in exchange for their loyalty and the payment of a tax. Tax receipts like this one were therefore very important to prove their status.
Many dhimmis played important and public roles in the empire. For instance, Syrian Christians played a significant role in translation initiatives. The most famous translator of the time was Hunayn ibn Ishaq, a Nestorianism Christian physician. Having mastered Arabic, Syriac, Greek and Persian, he translated more than a hundred works, specializing in medical and scientific texts. For this he was paid handsomely, as much as some provincial governors! Other dhimmis served the Abbasid caliphs as physicians, astronomers, tax collectors and even viziers.
This policy was born out of self-interest for the caliphs: during the Islamic expansion of the seventh and eighth centuries, very few Muslims had the administrative know-how to ensure the continuous day-to-day management of the cities they were conquering, and letting the local elites keep some form of power facilitated their surrender immensely. During the Abbasid times, this still held true: when Caliph al-Mansur (r. 754-775) attempted to remove dhimmis from his administration, he was soon compelled to return them to their positions due to their expertise.